This Presentation include's Basic input and output. Detail architecture of PLC. Input Module -Analog Sensors -Actuators -AC Inputs -DC Inputs Output Module -Relay -Transistors -Triac -Solenoid Valves CPU Programming Devices

1. Hardware Components of
PLC

2. About PLC
Power Supply
Central Processing Unit (CPU)
Input/output
Indicator Lights

4. Objectives
To understand and design basic input and output.
To study detail architecture of PLC.
Input Module
Output Module
CPU
Programming Devices

5. Inputs And Outputs
Inputs
Solenoid Valves
Lights
Motor Starters
Servo Motors
Outputs
Proximity Switches
Switches
Potentiometer
LVDT

6. Architecture of PLC

7. Input Module
• Voltage level.
• Current input.
• Conversion speed

8. Analog Sensors
Reed Switches
Optical Sensors

9. Actuators
Solenoids
Converts electrical energy into some form of
mechanical motion

10. DC Inputs
When we are using a sensor, we have to worry about its
output configuration.
If we are using a regular switch (toggle or pushbutton)
we typically don’t have to worry about it.
DC input modules allow to connect either PNP
(sourcing) or NPN (sinking)
transistor type devices to them.

11. AC Inputs

12. Output Module
• Voltage level
• Load Resistance
• Current Output

13. Relay
Most Common Type of Output
Use Rated Voltage and Rated Current
Essential for switching
large power loads.
Relay can switch large current
loads.
A relay is slow, can switch a
large current, has a shorter
lifetime and works with ac or dc

14. Transistor
Cannot Switch as Large load as a relay
Can only switch a dc current thus it is not used with
AC Voltage
BJT has slightly less switching capacity than MOSFET
Never exceed the PLC manufacturers maximum
switching current.
A transistor is fast, switches a small current, has a long
lifetime and works with dc only

15. Triac
Used to Control only AC Loads
Faster in Operation and has longer life than relay
output.
Inductive loads have a tendency to deliver a “back
current” when they turn on.
Typically a diode, varistor or other “snubber” circuit
should be used to protect the PLC output from any
damage.

16. Solenoid valves
A solenoid valve is an electromechanically operated
valve.
Fast and Safe Switching
High Reliability
Long service Life
Low Control Power
Compact Design

17. Central Processing Unit
 Reading the Input
 Executing the
Program in memory
 Updating the Output
 CPU makes a great number
of check-ups of the PLC
controller itself so eventual
errors would be discovered early

18. Memory And Power Supply
EPROM Memory
instead of FLASH
Memory
Most PLC’s Have 24 V(DC)
or 220V(AC) Power Supply

19. PLC Signal Flow
Processor Memory Output Modules
Programming Terminal
O:0/7
O:0/7
Output Devices
O:1/5
Input Module
Input Devices
Ladder Program
O:0/7
O:1/5
I:0/6
I:1/4
O:1/5
I:0/6
I:1/4
I:0/6
I:1/4
Input Data
Image Table
Output
Image Table

20. Programming Devices
The two Basic type of Programming devices are:
Mini programmers (Hand held Programmers)
Personal Computers

21. Applications of PLC
Travel Industry
Manufacturing Industry
Printing Industry
Food Industry

22. Conclusion
PLCs are used in many “Real World” applications.
PLC is designed to perform a single set of tasks, except
under real-time constraints and with superior
reliability and performance.
PLCs are designed to be extremely robust, often
capable of withstanding extreme temperatures,
humidity, vibration, and electrical noise.